SWIFT – UICOLLECTIONVIEW SCROLLTOITEMATINDEXPATH, not loaded before the animation is completed before the visible cell

UIView.animateWithDuration(animationSpeed, animations: {() -> Void in
 self.collectionView.layoutIfNeeded()
 self.collectionView.scrollToItemAtIndexPath( NSIndexPath(forItem:self.indexPathSelected.row, 
 inSection:0), 
 atScrollPosition: .CenteredHorizontally, 
 animated: true)

}))

override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
view.layoutIfNeeded()< br /> colView.scrollToItem(at: IndexPath(item: 4, section: 0), at: .centeredHorizontally, animated: true))

I have a UICollectionView with 142 cells. Can be seen at any time 7. 5.

I am moving a cell from indexPath 0 to 100.
But I also want to scroll to that new position.

The code below works fine. But it animates moving and scrolling, but then loads the cells to the center/moving cells before and after.
I think this is because the cells are reusable. But 142, I can’t preload all of them

It is not the best effect, I want to preload the cells around the new position, before and after indexPath 100 and 4, and then view the animation of moving and scrolling. Can you help?

UIView.animateWithDuration(animationSpeed, animations: {() -> Void in
 self.collectionView.layoutIfNeeded()
 self.collectionView.scrollToItemAtIndexPath( NSIndexPath(forItem:self.indexPathSelected.row, 
 inSection:0), 
 atScrollPosition: .CenteredHorizontally, 
 animated: true)

}))

Swift 3.0 OR up

add “view.layoutIfNeeded()” before implementing scrollToItem method, Ideally in viewWillAppear

override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
view.layoutIfNeeded()
 colView.scrollToItem(at: IndexPath(item : 4, section: 0), at: .centeredHorizontally, animated: true)}